Ocean, nature, critters, and recreation

Aug 10, 2010

White sharks making a comeback off California, expert says

It might come as unwelcome news to swimmers and surfers, but great
white sharks appear to be mounting a comeback off California.

"I think there are more sharks," Christopher Lowe, a professor at Cal State Long Beach and director of the university's Shark Lab, said during an exclusive phone interview. "And that's not a bad thing; it's a good thing."

It's
the first declaration by a prominent shark researcher that a recovery
of the embattled great white shark -- the world's most notorious
predator -- seems to be occurring.

A longstanding statewide
ban on fishing for white sharks, an increased survival rate among young
white sharks because of fishing gear restrictions, and an expanding sea
lion population as a prey source are chief reasons for the comeback.

Lowe,
who has performed extensive tagging of juvenile white sharks off
Southern California and has pored over data dating back generations,
said personal observations and increased incidental catch rates of
small white sharks by commercial fishermen help support his contention.

Salvador Jorgensen, leader of the white shark research team at Stanford University's Hopkins Marine Station, did not disagree with Lowe's assessment but was more guarded when asked for a response.

"If
what we are seeing is truly an increase in the white shark population
that would be a relief," Jorgensen said. "Currently we are finding that
the total number of adult white sharks along the west coast of North
America is much smaller than many people expected."

While the
prospect of great whites multiplying off the Golden State might trouble
beachgoers, particularly in the middle of summer, Lowe said he does not
believe a growing population would result in more attacks on humans.

"The
fact that we see so few adult white sharks around populated areas tends
to suggest that they don't want to be around places where people are,"
the scientist said. "People aren't being bumped. People aren't being
hit. My guess is that sharks are actually avoiding areas of high human
population."

Southern California is a nursery area for juvenile
great whites, who feed on small fishes, rays and other sharks during
the summer months. Some of these sharks, measuring to about seven feet,
are seen each summer by beachgoers.

There
have been only eight fatalities attributed to white sharks off
California dating to 1926, according to the University of Florida's International Shark Attack File. The last fatality involved an attack by an adult white shark on a swimmer off a northern San Diego County beach in April 2008.

Jorgensen
said a joint population study of adult white sharks by Stanford
University, U.C. Davis and Montana State University is still under peer
review, so he could not volunteer a number. Lowe and his colleagues also have produced a scientific paper under review, supporting a recovery. "Like Sal, I'm a little hesitant to reveal too much until the paper is fully accepted, but I think the data look pretty strong," Lowe said.

Adult great
whites congregate each fall near elephant seal rookeries off Central
California. A separate population gathers during the same period at
remote Guadalupe Island west of Baja California.

Among the
threats white sharks have faced globally are trophy hunting for jaws
and teeth -- which became widespread after the release of the movie "Jaws" in the mid-1970s -- and commercial fishing for fins and flesh.

It
almost seems implausible, in an era during which so many species of
sharks are overfished and believed to be in decline, that any species
could mount a comeback.

But considering the changing landscape
off California, a comeback and its timing make sense. The ban on
fishing for white sharks -- for sport or commercially -- was imposed in
1994. That same year, voters approved a measure outlawing the
deployment of gillnets within three miles of the California coast.

In
Southern California, this zone is where juvenile white sharks spend the
summer preying on small fishes, rays and other sharks, before swimming
into warmer Mexican waters during the winter.

White sharks are
still being caught unintentionally beyond the three-mile mark -- The
increase in these captures is what helps support evidence of a comeback
-- but those sticking closer to shore are no longer imperiled by the
indiscriminate nets, until they venture into Mexican waters.

Adult
white sharks, meanwhile, now have a seemingly endless bounty of sea
lions on which to prey, along with the elephant seals they prefer.

Sea lions, once routinely slaughtered by fishermen, were spared under the Marine Mammal Protection Act
of 1972. Ten years later, their population was estimated at 145,000 in
a range from the Sea of Cortez within Mexico to British Columbia,
Canada, with only 50,000 in the Southern California Bight.

According to the most recent National Marine Fisheries Service estimate, there there are at least 238,000 sea lions in U.S. waters, the majority of which reside off Southern California.

"So
if you add those two things together, you've got a restored forage base
for the adults and you've got better survivorship of the pups," Lowe
said. "So what we think we're seeing from the fishery catch data and
some of the other anecdotal pieces, is the actual recovery of the white
shark population."

The biologist added that while Southern
Californians should not expect a spike in shark attacks on humans,
those who spend lots of time in or near the ocean might witness more
sea lions with bite marks, and more surface attacks by white sharks on
the pinnipeds.

"I think the white shark population is going to
do what it's supposed to do: help regulate marine mammal populations,"
Lowe said, explaining that apex predators play a vital role in
maintaining a healthy marine ecosystem.

To be sure, fishermen
whose livelihoods are threatened by pesky sea lions, which decimate
catches and destroy gear, will cheer alongside marine conservation
groups for more signs of a white shark comeback.

Comments

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Yes , and I predicted this. This will be my third summer snorkeling in La Jolla. I have a snorkeling club. I found myself in the middle of the politics at The Children's Ocean Swimming Pool in La Jolla. After researching both sides and swimming there year around; I know that there are just way too many seals there and sea lions north of there and especially in the MPA, The Cove. Except for some stubborn ones on the back of the sea wall mixed with barnacles I can not find one live mussel. Seriously. That is a definite indicator of depletion of the underwater ecosystem and ability to support life, especially marine mammals that eat many pounds per day and are doubling and tripling their populations each year. They are not even allowed to die naturally as Rescue organizations keep releasing them over and over again. And people and seals (to some degree the lions) have become friendly. Very . Generations of seals have imprinted on humans at this Children's Bathing Pool, and come right up to people. They pet me. They are like labrador retrievers as far as disposition.One swam with me on a night dive for over an hour, petting me, and pressing his face to mine. He approached me, and I felt we were great diving buddies. Now the poor things are starving to death in their own feces penned in the concrete pool there. And here come the sharks to take care of man's poor marine mammal management. The agencies are calling the starvation a 'mystery' they do not want to admit their failure. Its no mystery, its the Law of Supply and Demand. Hope I taste alright.

You got to be kidding me! These marine biologists never cease to amaze me. For someone who is supposed to be so intelligent,why do they overlook the obvious? Great White sharks are extremely dangerous.
I used to hunt sharks,kill them and sell their meet to fish markets. It was my job. After catching a shark,I would immediately cut it's head off with a handsaw. Then I would gut it and remove it's fins. Now, it would be weighed and I would be paid. I enjoyed getting these man eaters out of the water. As far as the seals go, it was the Federal government who outlawed the taking of seals years ago, that is how the seals multiplied to fast. These seals eat all the lobster and abolone they can find. These things you don't learn out of a book, you must be on the water for years and see for yourself. Captain Michael R. Daniels aka Anchorboy46@yahoo.com

All I can say is that I would like it taped when the scientists take their families to the attack areas to swim. It will never happen, as they are saying to just stay out of the water. I lived in Oakland when the guy was killed there and fishermen tied a rope to his girlfriend, telling her to go and retrieve him. She did, and she got the keys to the city. That incident was mentioned in "Jaws". Also my family was ordered "Out of the water" by the helicopter circling overhead two days later. Lol, I was already out of the water, as I had spotted the dorsal fin before the order was given. How I laughed, as my mother and the rest of family wouldn't listen to me. They heard the guy in the helicopter, though, then they saw the dorsals. Mom thought we were safe, as the entire area we were in was man-made, and only three feet deep. Nope, sorry, she was wrong. Three feet deep is the ideal amount of water for a shark attack, which people need to know.

Lowes comment is off. Look Lowes the more numbers of anything , the more incidents of something.Humans,nature and space define the odds
plus the yet to be learned.
More Great Whites-OK- if that's ecologically sound.
However more people will get bit.

Typical, I'm going on a surf trip to Huntington Beach next month. I am always a little scared of sharks but I try to put it to the back of my mind as much as possible. It still would never stop me going in the water.